1. Field of the Invention
This invention relates to an image processing apparatus and method for correcting the image quality of an original image, and a recording medium.
2. Description of the Related Art
In general, image processing apparatuses execute white balance adjustment for correcting the brightness of an input image. In white balance adjustment, the adjustment degree and proper processing change depending on an image scene. When the conventional image processing apparatus is to perform white balance adjustment, it sets in advance a predetermined threshold for determining the image scene, compares a representative value representing the feature of image data to be adjusted with the threshold, and switches the white balance adjustment method with respect to the image data in accordance with the comparison result.
However, since the conventional white balance adjustment is done to mainly adjust the image brightness, white balance adjustment for a color image may result in unnatural color balance.
Further, since the conventional white balance adjustment processing is switched at the boundary of the threshold, white balance adjustment changes for image data having a value near the threshold as a representative value depending on whether the representative value is larger or smaller than the threshold value. For example, even when two image data have almost the same representative value and similar color tones, if their representative values are larger and smaller than the threshold, respectively, the two image data give greatly different impressions upon white balance adjustment processing.
An image processing apparatus, which has an interface with an external device and allows image input via the interface, can be connected to a plurality of types of image input devices.
If this apparatus is equipped with, e.g., three adjustment means for xe2x80x9ccontrast adjustmentxe2x80x9d, xe2x80x9ccolor balance adjustmentxe2x80x9d, and xe2x80x9clightness adjustmentxe2x80x9d, the apparatus adopts an image processing method of correcting an image input from each connected image input device using all the adjustment means, thereby achieving image quality adjustment corresponding to the characteristics of each input device.
In the conventional image processing apparatus, the order of correction processes by the respective adjustment means is determined in advance and cannot be changed. Depending on a connected input device, it may be preferable to change the processing order or not to execute specific processing. However, the conventional image processing apparatus cannot appropriately cope with such input device, so it is difficult to perform optimal correction in accordance with a plurality of connected input devices.
Accordingly, it is an object of the present invention to provide an image processing apparatus and method capable of performing proper white balance adjustment with good color balance, and a recording medium.
According to the present invention, the foregoing object is attained by providing an image processing apparatus comprising: input means for inputting color image data; representative value calculation means for calculating a representative value for each color component forming the color image data; adjustment coefficient calculation means for calculating an adjustment coefficient based on the representative value for correcting the color image data; and image correction means for performing correction based on the adjustment coefficient for each color component of the color image data.
Thus, the white balance adjustment coefficient can be determined in accordance with the representative value of each color component representing image features.
And it is another object of the present invention to provide an image processing apparatus and method for performing proper white balance adjustment with good color balance without greatly changing adjustment results between similar images, and a recording medium.
According to the present invention, the foregoing object is attained by further providing: adjustment coefficient correction means for correcting the adjustment coefficient calculated by said adjustment coefficient calculation means wherein said adjustment coefficient correction means corrects the adjustment coefficient so as to be consecutive with respect to each value of the color image data.
The white balance adjustment coefficient can be continuously corrected in accordance with image features.
And it is another object of the present invention to provide an image processing apparatus and method for performing proper white balance adjustment in accordance with an input device, and a recording medium.
According to the present invention, the foregoing object is attained by providing an image processing apparatus comprising: wherein the input means inputs the color image data via an input device, and the adjustment coefficient correction means corrects the adjustment coefficient in accordance with a characteristic of the input device.
Proper white balance adjustment based on input device characteristics can be realized.
And it is another object of the present invention to provide an image processing apparatus and method capable of performing optimal correction in accordance with an input device when a plurality of types of correction processes are done for image data, and a recording medium.
According to the present invention, the foregoing object is attained by providing an image processing apparatus comprising: an image processing apparatus capable of performing correction processing by a plurality of types of correction methods for image data, comprising: image input means for inputting image data from an input device; specifying means for specifying characteristics of the input device; and correction control means for controlling a plurality of types of correction processes for the image data on the basis of the characteristics of the input device.
A plurality of correction processes for image data can be controlled based on input device characteristics to realize optimal correction.
The invention is particularly advantageous since the white balance adjustment coefficient can be determined for each color in accordance with image features to realize proper white balance adjustment with good balance.
The white balance adjustment coefficient can be continuously corrected in accordance with image features to realize proper white balance adjustment with good balance while preventing the adjustment results of similar images from becoming greatly different from each other.
Further, optimal image correction corresponding to input device characteristics can be realized.
Other features and advantages of the present invention will be apparent from the following description taken in conjunction with the accompanying drawings, in which like reference characters designate the same or similar parts throughout the figures thereof.